This invention relates to a novel method of treatment and a novel pharmaceutical composition related thereto.
International Patent Application No. WO 99/18967 describes pharmaceutical compositions for treating chronic and neuropathic pain which comprises an analgesic amount of an opioid and an opioid potentiating amount of a CCK antagonist. WO ""967 describes the use of both CCK-A (CCK-1) antagonists and CCK-B (CCK-2) antagonists, although it is described that, generally, CCK-B (CCK-2) antagonists are preferred. Moreover, page 2, lines 6 to 8 of WO ""967 describes that CCK-A (CCK-1) antagonists may be suitable, but only at relatively higher dosages.
One specific CCK-A (CCK-1) antagonist which is mentioned in WO 99/18967 is devazepide (Devacade(copyright)), which is 3s-(-)-1,3-dihydro-3-(2-indolecarbonylamino)-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one.
Devazepide is commonly administered alongside an opioid analgesic, e.g. such as morphine. However, in normal doses, the commonest side-effects of morphine and other opioid analgesics are nausea, vomiting, constipation, drowsiness, and confusion; tolerance generally develops with long-term use, but not to constipation which is the most common undesirable side effect of morphine treatment.
International Patent Application No. WO 99/18967 specifically describes a pharmaceutical formulation comprising a CCK antagonist, such as devazepide, an opioid and a biphasic carrier, comprising a glyceride derivative organic phase. This application suggests the possible use of a surfactant, especially when the formulation is in the form of an oil-in-water emulsion.
We have now surprisingly found that a method of treatment of a patient requiring analgesia which comprises administering a monophasic form of devazepide which may be prepared with a surfactant. The use of a surfactant is advantageous in that, inter alia, it improves the powder flow and/or separation properties of solid devazepide and also reduces or mitigates the undesirable side effects of opioid administration, e.g. constipation.
Thus, according to the invention we provide a method of treatment of a patient requiring analgesia which comprises the separate, simultaneous or sequential administration of a therapeutically effective amount of an opioid analgesic, devazepide and a pharmaceutically acceptable surfactant wherein the daily dosage of devazepide is up to 0.7 mg/kg/day.